In breeding of ruminants, simultaneous feeding of the rumen bypass formulation with fodders has been spreading among livestock farmers because such method is dietetically and clinically advantageous. However, there is a problem that livestock do not like the taste of rumen bypass formulation, and that a work to individually weigh and feed the rumen bypass formulation is quite troublesome for the livestock farmers. On the other hand, the use of feed pellets have also been spread among the livestock farmers since it can reduce labors required for feeding operation and a give a chance to automate the operation.
Therefore, it is expected that a feed pellet comprising the rumen bypass formulation as its component can be an useful feed for livestock, as it can utilize both advantages of the rumen bypass formulation and the feed pellet and may solve the problems described above.
The rumen bypass formulation for ruminants described above comprises one or more of various amino acids, various vitamins and other biologically active principles, and which has a function to restrict the elution and the microbiological degradation of the biologically active principles in a rumen (first ruminant stomach) of ruminants while to allow the elution and absorption of the biologically active principles in digestive organs after fourth ruminant stomach. The concept and many practical examples of the rumen bypass formulation have already been known to the public.
However, the rumen bypass formulation in the past appear to have been composed without considering the pelletization thereof. Such rumen bypass formulations, either in a form protectively coating the particles of biologically active principles or in a form wherein biologically active principles are dispersed in oils and fats, are destroyed due to a mechanical stress, humidification and heating which are imposed during the pelletization process to the extent that the original shape thereof cannot be distinguished.
As several examples are shown in the comparative examples in the present specification later, the inventors of the present invention attempted to formulate these known rumen bypass formulations, then tried the pelletization of the rumen bypass formulation combined with feedstuffs to have a feed pellet. However, in every cases, the rumen bypass formulation therein were destroyed, so that the rumen bypass effect of the pellets was lost or extremely ceased, which made the formulation practically useless.
In U.S. Pat. No. 5,068,108, the concept of providing the resistance to pelletization, which is to mechanically reinforce the rumen bypass formulation by combining macromolecular substances therein is described. However, the examples described therein teach just the composition of the rumen bypass formulation, but the performance thereof and the evaluation of the rumen bypass effect after pelletization were not described at all.
The inventors of the present invention could not obtain a desired feed pellet according to the description of the example in the above U.S. Patent. The feed pellets obtained were insufficient in mechanical strength even by combining the rumen bypass formulation with macromolecular substance, and the rumen bypass formulation were destroyed during pelletizing process by a pellet mill to an extent that the original shape thereof can not be distinguished therefore, the rumen bypass effect of the feed pellet was extremely ceased, accordingly.
In the Gazette of Japanese Patent Laid-opened No. Hei 4-79844, a method to prevent the elution of a protective coat, which dissolve when it contacted to amidic feeds, comprising by forming a second coat over the circumference of the rumen bypass formulation coated with said protective coat is disclosed, however, there is not provided the concept as to the resistance of said double-coated rumen bypass formulation against mechanical stress, humidification and heating, and the pelletization of such formulation in the disclosure.
The feed pellet for ruminants disclosed in the Gazette of Japanese Patent Laid-opened No. Hei 4-218342 is formed according to a method which molds a rumen bypass formulation placed in a cavity together with injected melting substance therein by cooling them to solidify in a form of pellets therefore, it is different from the pellets of the present invention which is molded by using a common rotary die or other type of pellet mill. Furthermore, the result that conventional rumen bypass formulations were easily destroyed during pelletization by using the rotary die pellet mill or the like is described in the specification of the Gazette described above.